From frame-mounted rotatable antennas, signals are transmitted to a stationary installation for processing and evaluation. In, for instance, radar antennas, the rotational angular position of the antenna is relevant for the evaluation of the signals. The transmission occurs via a transmitter, a rotating member, which is theoretically coaxial with the axis of rotation of the antenna, to a stationary installation for processing the signals. Therefore, in such antennas there is at least one angle-transducing device connected to one of the rotary parts of the antenna.
The prior-art technique of suspending the rotating member is inaccurate owing to the fact that in actual practice it is very difficult to mount the shaft of the rotating member concentrically with the antenna shaft, so that the angle-transducing device provides correct information on the rotational angular position of the antenna. There will always be a certain eccentric and inclination error between the antenna shaft and the mounting of the shaft, which causes errors in the angle transducing.
If the stationary part is rigidly fixed to the frame, forces will arise, which are a great stress on the components included in the antenna suspension. This results in a short service life, short service intervals and great expenses for repair and spare parts.